Foundation和CoreFoundation

　　1、Foundation框架提供OC接口
　　2、Core Foundation框架提供C语言接口
　　3、Foundation对象是OC对象，在MRC下需要手动管理内存，在ARC下不需要手动管理内存
　　4、CoreFoundation对象是C对象，在MRC和ARC下都需要手动管理内存
　　5、数据类型之间的转换可以使用__bridge、__bridge_retained、__bridge_transfer
　　CFStringRef 转 NSString #pragma mark - CFStringRef 转 NSString -(void)CTypeTransformToOCType { #if 0     CFStringRef cString = CFStringCreateWithCString(NULL, ＂C语言＂, kCFStringEncodingUTF8);     NSString* ocString = (__bridge  NSString*)cString;     NSLog(@＂ocString:%@＂,ocString); #endif #if 1     CFStringRef cString = CFStringCreateWithCString(NULL, ＂C++＂, kCFStringEncodingASCII);     NSString* ocString = (__bridge_transfer  NSString*)cString;     NSLog(@＂ocString:%@＂,ocString); #endif }
　　NSString 转 CFStringRef #pragma mark - NSString 转 CFStringRef -(void)OCTypeTransformToCType { #if 0     NSString* ocString = @＂OC字符串对象＂;     CFStringRef cString = (__bridge  CFStringRef)ocString;     NSLog(@＂cString:%@＂,cString); #endif #if 1     NSString* ocString = @＂OC字符串对象＂;     CFStringRef cString = (__bridge_retained  CFStringRef)ocString;     NSLog(@＂cString:%@＂,cString); #endif }
　　应用场景 -(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {     NSString *type = [info objectForKey:UIImagePickerControllerMediaType];          if([type isEqualToString:(__bridge NSString*)kUTTypeMovie]){              }else if([type isEqualToString:(__bridge NSString*)kUTTypeImage]){              } }